The enzyme RNA-directed DNA polymerase, also known as Reverse Transcriptase, from avian myeloblastosis virus (and other sources) provides a possible means for synthesizing a DNA gene directly from isolated messenger RNA. Unfortunately, the DNA product so far obtained is only a partial copy of the messenger RNA template. It is desired, therefore, to learn the mechanism of action of the enzyme in order to establish conditions whereby a complete (and active) DNA gene can be transcribed from a globin messenger RNA. Detailed studies on the mechanism of action of the enzyme RNA-directed DNA polymerase are being carried out.